Can an airbox mod make you run too lean?

Hi I'm new to the Forum I'm hoping to pick up a Grom this weekend I was talking to the dealer and he said that he has had 3 come back with blown heads from running too lean from people modifying the airbox so they have to check for tampering and it voids the warranty if any bolt is removed. That worries me because one of the first things I was planning on doing was modding the airbox, also I was thinking about a Two Brothers S1R exhaust for it. Would this lean it out too much and should I get an EFI controller of any sort? I'm new to tuning and motorcycles in general I'm hoping to make this my first and enjoy it. Thanks in advance guys.